Alloys and process for improving workability of same



Patented Sept. 29, 1931- UNITED STATES- PATENT OFFICE NORMAN B. FILLING,OI ELIZABETH, NEW JERSEY, ASBIGNOR, BY MEBNE ASSIGN- MENTS, TO THEINTERNATIONAL.NICKEL COMPANY, INC., 01 NEW YORK, N. Y., A

CORPORATION OF DELAWARE -ALLOYS AND PROCESS FOR IMPROVING WORKABILITY OFSAME No Drawing.

This invention relates to an improvement in malleable nickel, alloyscontaimng nickel and to other alloys and to an improved process forproducing the same, particularly in combining therewith analkaline-earth metal, either elemental or in alloyed form.

One of the objects of this invention is to improve the ductility,malleability and working properties of such alloys and increase theircapacity for being worked by such operations as forging, hot and coldrolling, drawing, pressing or other processes.

It has recently been found that the addition of a relatively smallamount of an alkaline-earth metal to alloys containing nickel,

and to other alloys, imparts an enhancement in the properties indicatedabove without adversely affecting other desirable properties.

Calcium, as well as barium and strontium has been found to be especiallybeneficial in connection with the production of malleable nickel,iron-nickel alloys and iron-nickelchromium alloys, and will be cited asan illustrative example.

Though various ways of incorporating calcium, barium or strontium withthe alloy will be described, it is to be understood that the inventionis not limited to theseor any other processes of applying the same. Inparticular, the invention is directed to the production of malleablenickel alloys, and to other alloys, resulting from combining therewithcalcium, barium or strontium, by whatever process employed.

Preferably, the calcium, barium or strontium is added to the nickel orother alloys while they are molten and just before pouring. Two reasonsfor so acting are that calcium is highly reactive and vaporizes rapidly.

Ithas been found that calcium, barium or strontium is able to replacemagnesium or manganese or both in many alloys containing' nickel,thereby avoiding certain undesirable characteristics as will bedisclosed more fully hereafter.

With respect to magnesium it is the practice to employ this element asan addition agent in connection with the production of Application filedSeptember 80, 1987. Serial No. 223,238.

malleable nickel and malleable alloys of mckel, such as nickel-copper,nickel-chrom um, etc. Magnesium is, however, partically insoluble inmolten iron or chromium, and the presence of relatively smallpercentages of either of these elements in nickel alloys restrict thesolubility of magnesium so much that the'full benefit of its presence isnot readily obtained. Calcium, as well as barlum and strontium on theother hand dissolves readily and quietly in iron, in

nickel and in ferrous alloys containingnickel and chromium.

With respect to manganese, it is usually considered necessary bymetallurgists to have this element present in alloys containmg nickel infrom severaltenths percent to as much as several percent in order tosecure a practical degree of malleability in the alloy to permit workingby forging, rolling, pressing and the like. However, other propertiesmay often be adversely affected by this content of.manganese, which istolerated as a concession to the necessary property of malleability. Byemploying an alkaline-earth metal, such as calcium, bar- 1um orstrontium as herein described, it is possible to secure malleable ingotsentirely free from manganese, and avoid the undesirable eflects. Evenwhere an alloy contains manganese the forgeability of the same isgenerally improved by the addition of a small amount of calcium, bariumor strontium. 1 y

In general, the amount of calcium, barium or strontium required isbetween .005% and .5% of the entire melt by weight.

It will be seen, therefore, that calcium, barium or strontium mayreadily and advantageously displace both magnesium and manganese inmalleable nickel or alloys containing nickel, and these not only becomeinvested with the degree of malleability imparted to them by calcium orits equivalents, above noted, but avoid the acquisition of otherproperties limiting their full scope ofadoption. In addition, calcium,barium or strontium has a property not possessed by magnesium, and thatis its ability to lot dissolve in and be alloyed with iron or alloysthereof.

As already indicated, the incorporation of calcium, barium or strontiumin the melted alloy may be carried out in many ways, as for instance asfollows: The alloying mixture of elements, for instance, nickel and ironis fused in a furnace and refined or treated in any customary manner tosecure predetermined properties, excluding or including malleability;then, just before pouring, calcium, barium or strontium or an alloythereof is introduced into the melt. The reason why an alkaline-earthmetal such as calcium is added as the last step' in th e process isbecause calcium and the other alkaline-earth metals are highlyvolatile'and reactive and the shorter the period elapsing between itsincorporation in the melt and solidification the greater will be theconservation of calcium and/or other alkaline-earth metals used.

Since calcium, barium and strontium and most of its suitable alloys areof lower specific gravity than the melt it is desirable to force theformer to the bottom of the melt to aid in securing its complete anduniform solution. This may be done in any convenient manner, such as byattaching the calcium, barium and strontium or its alloy to a rod, orother device which can be quickstrontium,

ly thrust to the bottom of the melt.

It may happen that some calcium, barium and strontium will float to thesurface before it is completely absorbed by the melt. In such aninstance the calcium, barium and strontium burns to an infusible oxidewhich may become entangled with the melt in subsequent handling. Toavoid this possibility, a thin layer of fused siliceous slag may beprovided on the surface of the melt prior to the addition of calcium,barium and or if this is not convenient a little silica sand may bespread over in an amount about equal to the weight of calcium, bariumand strontium added. The heat of oxidation of the excess calcium, bariumand strontium then suffices to produce a fused calcium, barium andstrontium silicate which separates readily from the melt.

The amount of calcium, barium and strontium which is usuallysatisfactory to comingle with the melt may be between about .005% and.5%, by weight, of the entire melt. An excessive amount of calcium,barium and strontium is to be avoided, since calcium, barium andstrontium has a limited solid solubility in iron alloys andin nickelalloys, and if present in undissolved form is apt to occur as a brittleconstituent of low fusibility which in itself'impairs malleability.

It was found that in the case of an ironnickel alloy containing 65%nickel and about .7% manganese, the alloy'was rather imperfectlyforgeable, tion of .05% to .09% ability was excellent.

but upon the addiof calcium, the forge- However, further additions u to.15% brought about an entire loss of f drgeability. It will be obvious,therefore, that for this alloy and the circumstances of its preparation,the optium calcium addition is between 05% and 09%. Due to imperfectassimilation by the melt, the residual calcium content determinable bychemical analysis is generally less than the amount added. It will berecognized that if the alloy to be treated departs much in compositionfrom the example just cited, the optimum calcium addition may likewisechange, and for this reason the invention is not limited to any specificamount of calcium or calcium-alloy addition or content, except as willgive the results desired.

The calcium may be used as the elementary metal, or as an alloy withsome other metal or metals. Elemental calcium is highly reactive withatmospheric moisture and soon becomes enclosed in a hydrated coatingwhich sometimes interferes with its assimilation in the melt. A calciumalloy may have several advantages over calcium metal, such as increasedspecific gravity, increased stability against atmospheric attack, andimproved fusibility of the alloy or of its oxidized products.Considerable latitude in the nature of such calcium alloys is allowableand the calcium content may range between 5% and 95%. Alloys of calciumwith copper, with nickel or with silicon, and containing 30% to calcium,have been found suitable.

As an example to show how calcium improves the workability of nickelalloys, there was first prepared an alloy of 50% iron and 50% Monelmetal by fusion with a small amount of ferro-manganese and ferro-siliconyielding, on analysis: manganese 56% and silicon .15%. An ingot of thismelt was forged at 1150 C. and began to crack after a few blows of thehammer. Continued forging in an attempt to reduce it to a slab suit'ablefor rolling was unsuccessful in that these cracks spread, leaving deeplyserrated edges. A portion was trimmed free from edge defects and coldrolled, but split apart after a slight reduction in thicknem.

There was then prepared a second melt, similar tothe first except forthe addition just before casting of about .1% calcium as acalcium-silicon. alloy, which analyzed manganese 155% and silicon 21%.An ingot of this melt was'then subjected to forging as above to a slab 3inches wide by of an inch thick, which was then cold rolled Withoutdifliculty to a sheet .050 inch thick.

Entirely malleable alloys may be produced in the complete absence ofmanganese by means of this calcium treatment. However, it is firsthighly desirable to deoxidize the melt, which may be done with a littlesilicon or aluminum.

The advantages of these manganese-free alloys lies in the elimination ofundesirable effects which manganese exerts on various physicalproperties of the alloy, but these are merely incidental improvements inthe characteristics of a calcium-treated alloy.

Though there are described herein, as examples, the treatment of aniron-nickel alloy and of an iron-nickel-copper alloy with calcium,barium or strontium, the invention is not limited to the treatment withcalcium, barium or strontium of these alloys or any particular types orcompositions of alloy. It has been found that calcium, barium orstrontium improves also the malleability of many alloys of iron, nickeland chromium (products which are extremely workable and resistant totarnish, rust and corrosion), and which form the subject of a copendingapplication of Paul D. Merica, Serial No. 223,243, filed September 30,1927, entitled Tarnish resistant and rust proof alloys, and it appearsthat calcium, barium or strontium acts similarly with respect to manyother alloys of nickel.

The expression alkaline-earth metals as used in the claims excludes themetals magnesium and beryllium.

The invention herein has been described for particular purposes, but itis to be understood that there may be modifications and changes whichare to be considered as being claims.

What is claimed is 1. The process of producing alloys containing nickelwhich includes deoxidizing the principal melt and subsequently addingthereto a metal of the alkaline earth group.

2. The method of producing alloys containing nickel which includesdeoxidizing the principal melt and subsequently adding thereto between.005% and .5% of a metal of the alkaline earth grou 3. The method ofprorlilcing alloys containing nickel which includes deoxidizingthe'principal melt and subsequently adding thereto an alloy containing5% to 95% of a metal of the alkaline earth group.

4. The process of producing-alloys containing nickel which .includesdeoxidizing the principal melt and subsequently adding thereto calcium.

5. The process of producing alloys containing nickel which-includesdexodizing the principal melt and subsequently adding thereto between.005% and .5% of calcium by weight of the entire melt.

6. The method of producing alloys containin nickel which includesdeoxidizing the principal meltand subsequently adding within the scopeof the following thereto an alloy containing 5% to 95% of calcium.

7. The process of improving the workability of alloys containing nickelwhich consists in fusing said, alloys, providing at the surface thereofa layer of fused siliceous material, and introducinginto said meltcalcium.

8. The process of improving the workability of alloys which consists infusing said alloys in a suitable furnace, applying to the surfacethereof a layer of fused siliceous material, introducing into said meltcalcium in an amount about equal to the weight of said siliceousmaterial, and permitting said siliceous material to fuse with excess ofcalcium.

9. The process of improving the workability of alloys containing nickelwhich consists in fusing said alloys, providing at the surface thereof alayer of unfused siliceous material and introducing into said meltcalcium. I

10. The process of improving the workability of alloys containing mckelWlJlCh consists in fusing said alloys and introducing into the melt acalcium alloy, the oxidized products of which are fusible.

In testimony whereof I have hereunto set In hand. I

y NORMAN B. FILLING.

